Carlsbad has decided to proceed with a feasibility study of whether it should build a solar power farm on 30 to 40 acres in a rarely visited corner of the city. The site is at the city’s Maerkle Reservoir, near the border of Oceanside and Vista, where Carlsbad owns about 100 acres including the 17-acre reservoir topped by a floating fabric cover. One of the hurdles is the location, said Amanda Flesse, general manager for the Carlsbad Municipal Water District. The only easy access is from a paved road through Vista, although it also can be reached from El Camino Real in Carlsbad over the narrow, unpaved Sunny Creek Road. Also, recent fires at lithium-ion battery storage facilities in Escondido and elsewhere have raised concerns about possible fires, Flesse said.